I noticed, while watching The Ten Commandments, that a good number of characters make prophetic predictions about what will happen in the future. And at first, all of them come true. Especially notable is when Bithia makes Mamnet swear not to tell anyone that Moses is Hebrew and warns her that "the day you break that oath will be the last your eyes shall ever see." This prediction comes true, but does so for reasons that Bithia could not have had anything to do with. Even Rameses gets in on the action at one point. But beginning right after Nefertiri kills Mamnet (which is the event that kicks off Moses eventually being kicked out of Egypt), all this breaks down. After that point, only predictions made by Moses come true. Rameses makes some attempts to state what will happen, but even actions over which he has complete control—like whether or not he kills Nefertiri near-ish the end of the movie—do not come out as he predicted. —JurassicMosquito
All bar one: Rameses' promise/prediction to his father on his deathbed that he will make Egypt great among the nations. That much is true; Rameses II was known as "the Builder" and basically inducted Egypt into a golden age of prosperity. (Well, aside from the alleged destruction of his entire army by a certain Hebrew God, but that's another story.)
The idea of Ramses II being the unnamed Pharoah from the Bible pretty much comes from this movie anyway. Most scholars put the Exodus as centuries away from his rule, often during the rule of Ahkenaton.